During our studies of the cultured human fibroblasts (CHF) in cholesterol ester storage disease it became apparent that CHF offered a useful in vitro system for compositional, ultrastructural and enzymological studies of certain diseases of lipid metabolism. Preliminary studies of CHF from some patients with Type II hyperlipoproteinemia suggest that some of these patients have increased amounts of lipid in their cultured skin fibroblast. The aim of this study is to compare the quantitative lipid analysis, triglyceride acid hydrolase content, cholesteryl ester acid hydrolase content and ultrastructural composition of cultured human skin fibroblasts from infants, children and adults affected by Type II hyperlipoproteinemia (Fredrickson and Levy) with age matched control subjects. This study will determine answers to the following questions: 1. Dose the lipid composition of Type II hyperlipoproteinemia differ from that of normal individuals in 3 age groups? 2. What is the noraml lipid composition of CHF under relatively standard, simple cultured conditions? 3. Can the ultrastructure be related to lipid composition or acid hydrolase activity? 4. What is the acid lipase content of CHF? Does Lipase activity correlate with lipid composition?